Lamp base solder trimming apparatus



Sept- 19, 19 1 o. KVET 3,000,272

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Filed Oct. 13, 1958 9 His A t l," w-ne e United States Patent 3 000,272LAMP BASE SOLDEIE TRIMMING APPARATUS Otto Kvet, South Euclid, Ohio,assignor to General Electric Company, a corporation of New York FiledOct. 13, 1958, Ser. No. 766,778 2 Claims. (Cl. 90-14) My inventionrelates generally to apparatus for the manufacture of electric lamps andmore particularly to the basing or finishing operation wherein the baseof the lamp is assembled with the bulb or envelope and the leadin wiresextending from the bulb are united by globules of solder with contactmembers on the base. Still more particularly, my invention relates tonovel apparatus for trimming the solder globules.

Certain multiple filament incandescent lamps of the so-called three-wayor three-lite type having a pair of filaments of different wattages inthe envelope, are provided with a base comprising a metal screw shellcarrying at its end a center contact and a concentric intermediate ringcontact with the end contact at a higher elevation than the ringcontact. A common lead-in wire from one end of each of the filaments isconnected to the base shell, and 'a lead-in wire from the other end ofeach filament is connected and attached to the respective end and ringcontacts by a globule of solder on the upper surface of the contact.There has been some difficulty with such lamps when installed in theusers socket in that sometimes one filament would light and the otherwould not. It has been found that this is often caused by irregularheights of the solder globules. If one or the other of the globules ofsolder is too high, the lamp will not be screwed into the socket quitefar enough and there may be no contact at the other terminal, especiallyif the globule of solder there happens to be low.

It is an object of my invention to provide apparatus which will overcomethis difiiculty by cutting both globules of solder down to a properheight. Further objects and advantages of my invention will appear fromthe following detailed description of a species thereof and from thedrawings wherein:

FIG. 1 is a perspective View of trimming apparatus comprising myinvention;

FIG. 2 is an elevation, in section, showing the cutter member inoperative relation to a lamp base; and

FIG. 3 is a perspective view of the cutter member.

Referring to FIG. 1 of the drawing, the trimming mechanism is shown atone station of a so-called finishing machine which may be generally ofthe type shown in Patent 1,708,756, Fagan et al., and which comprises aturret, -a fragment of which is shown at 1, and which has mounted at itsperiphery a plurality of heads or lamp holder means 2 which areperiodically indexed from station to statiton by suitable indexingmeans. The head 2 comprises a bracket 3 in which is supported a verticalspindle 4 which is spring-loaded to be normally urged upward and whichis lowered for loading and unloading purposes by engagement of a roller5 on the lower end thereof with a suitable cam arranged along the pathof travel of the roller. At its upper end, the spindle 4 carries threefingers 6 forming a cradle for the lower bulbous end portion of theglass bulb 7 of a lamp 8.

The lamp 8 has attached to the upper end of its bulb 7 a base comprisinga screw-threaded metal shell 9 having attached to its upper end aninsulating web 10 (FIG. 2), of glass or organic plastic for example,having frustoconical portions in which are secured an intermediatering-shaped metal contact 11 and an end contact eyelet 12, the endcontact 12 being at 'a higher level than the ring contact 11. The bulb 7contains a pair of filaments and a plurality of lead-in wires (notshown). One of the lead-in wires is connected to an end of bothfilaments and Patented Sept. 19, 1961 extends outwardly from the bulband is connected to the base shell 9 in any desired manner, as by a dropof solder 13 or by welding; two other lead-in wires are connected to theends of respective filaments and extend from the 'bulb 7, one lead-inwire extending through the eyelet end contact 11 and being attachedthereto by a globule of solder 14, and the other lead-in wire extendingthrough an aperture in the ring contact 11 and being attached thereto bya globule of solder 15.

The lamp 8 is firmly held in the head 2 by upward pressure of thespindle 4 which presses the upper periphery of the base shell 9 againsta stationary apertured base plate or holder 16 which is fixedly attachedto the upper end of the bracket 3, the end and ring contacts 11 and 12being exposed above said plate 16.

In accordance with my invention, the solder globules 14 and 15 aretrimmed to a predetermined lever by a cutter member 17 having a centralor inner end face 18 with cutting teeth in its surface, and an outerconcentric end face 19 also provided with cutting teeth. The surface offace 18 is recessed within and spaced vertically above the surface offace 19 a distance substantially equal to the vertical spacing betweenthe upper surfaces of end contact 12 and ring contact 11. The face 18 ispart of a circular head portion 20 having an axially extending stem orshank 21, and the face 19 is part of a ring-shaped portion 20surrounding the head portion 20 and secured thereto by a 'set screw 22.A stop pin 23 projects axially downward from the head portion 20 andbeyond the surface of face 19 a short distance equal to the desiredfinished height of the solder globules 14 and 15; the pin is secured inan axial bore in head portion 20 by a set screw 24.

As best seen in FIG. 2, the cutter 17 is mounted with its vertical axis25 offset from the vertical axis 26 of the holder members 4, 6 and 16and the lamp 8 therein, preferably a distance approximately equal to themedial radius of the ring contact 11, and is arranged so that the pin 23engages the ring contact 11 at a point diametrically opposite the solderglobule 15.

Suitable mechanism is provided for rotating the cutter 17 about its axisand for reciprocating it vertically toward and away from the head 2 andthe lamp 8 therein. As herein illustrated, the cutter is rotated by anelectric motor 27 (FIG. 1) which is lowered and raised by a cam 28 inproper timed relationship with the dwell period of the indexing cycle ofturret 1. The cutter 17 is supported by engagement of its shank 21 withthe interior of the hollowed shaft 29 of motor 27, and is resilientlycoupled thereto by a helical spring 30 surrounding the shaft 29 andcompressed between the upper surface of the head portion 20 and ashoulder 31 on said shaft. The cutter '17 is free to move longitudinallyrelative to the shaft 29 a distance determined by the engagement of apin 32 on shank 21 with the walls of apertures 33 in said shaft.

The motor 27 mounted on a plate 34 which is guided for vertical movementalong posts 35 and 36 upstanding from a stationary table 37. The plate34 is actuated through a link 38, arm 39, shaft 40, arm 41, push rod 42,and arm 43 which carries a roller 44 engaging the surface of the edgecam 28. During indexing of the turret 1, the motor 27 and cutter 17 areheld in their uppermost positions by engagement of the roller 44 with ahigh uniform portion 45 of the cam 28, and when the head 2 comes to restduring the dwell period of the turret, the roller '44 moves down to andalong the low portion 46 of the cam 28 to lower the motor 27 and cutter17, the motor 27 preferably being connected to rotate the cutter 17continuously and directly at a speed of 1725 r.p.m., for instance. Dueto the weight of the motor 27, the actuating linkage is preferablypartially counterbalanced by a spring-loaded arm 47 which is fixed toshaft 40 and 3 is connected at its free end to a spring 48 anchored totable 37. It will be understood that the shaft 49 for cam 28 isconnected with the shaft of the indexing cam (not shovm) for turret 1 soas to make one revolution for each indexing cycle of the turret.

In the operation of the device, when the head 2 comes to rest at thestation occupied by the trimming mechanism, the revolving cutter 17 islowered by the cam 28 to bring the cutting surfaces 18 and 19 intoengagement with the solder globules 14 and 15, respectively, and trimthem to a desired height determined by the engagement of the stop pin 23with the ring contact 11 of the lamp base. As shown in FIG. 3, the teethin the cutting faces '18 and 19 are preferably of spiral shape to throwthe solder cuttings outwardly away from the lamp base. However, in orderto definitely assure the absence of cuttings on the top of the base, arotary brush may be arranged to sweep them oil? at the next stationtaken by the head 2 when it is indexed away from the solder trimmingstation. 7

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In an electric lamp making apparatus, the combination of lamp holdermeans having a vertical axis for supporting a lamp comprising a bulbhaving a base at the upper end thereof with a center contact and aconcentric ring contact at the upper end of the base and with the centercontact spaced vertically from and at a level above the ring contact,and a globule of solder on the upper surface of each said center andringcontact connecting thereto respective lead-in wires extending fromthe said bulb, said holder means holding said lamp with its centercontact in the said axis of the holder, and solder trimming mechanismcomprising a cutter arranged to be above said holder means and havinginner and outer concentric lower end faces with cutting teeth therein,the said inner face being recessed within the said outer face so thatthe said faces are spaced apart vertically a predetermined distancecorresponding to the vertical spacing of said center and ring contactsof said lamp base, a stop pin projecting axially downward from the innerface of said cutter a predetermined small distance beyond the outer facethereof, means mounting said cutter with its vertical axis offset fromthe vertical axis of the lamp holder means a distance approximatelyequal to the medial radius of the ring contact on the lamp base, meansfor rotating said cutter about its axis and urging it resilientlydownward to bring the stop pin thereon into engagement with a portion ofthe ring contact of the lamp base approximately diametrically oppositethe solder globule thereon whereby to trim down to predetermined heightsthe respective solder globules on said center and ring contacts.

2. Apparatus as set forth in claim 1, wherein the teeth on the faces ofsaid cutter are of spiral shape.

References Cited in the file of this patent UNITED STATES PATENTS1,785,978 Quinn Dec. 23, 1930 1,997,694 Mon'ck et a1 Apr. 16, 19352,069,386 Paluclm' Feb. 2, 1937 2,454,269 Braucher Nov. 23, 1948FOREIGN, PATENTS 154,912 Great Britain 1920

